The present invention relates to a step for escalators comprising a tread and an arcuate skirt adjoining the tread. The tread and the skirt have reinforcing ribs and/or reinforcing spars arranged on an inner surface in order to reinforce the step. A connecting structure for connecting the step to a drive arrangement is provided between a front edge region of the tread, as seen in the direction of travel, and a remote edge region of the skirt. It is preferred that the step be produced from a light-metal casting.
In order to convey people in public places, escalators are used as an alternative to lifts. The escalator step has to meet various requirements. It is necessary for the step to be lightweight and stable and not to be affected by dirt and damage. The individual steps, which are produced and used in large numbers, have to be produced with narrow tolerances, as far as the dimensional accuracy is concerned, even in the case of temperature fluctuations.
An escalator step is known from EP 945 391 A2. The step is produced, in a first production stage, from glass-fibre-reinforced plastic by injection moulding. In order to give the individual step the necessary stability, the step is reinforced in the rear edge region of the tread, transversely to the direction of travel of the step, with a hollow metal profile. In a further process stage, following the injection moulding, the metal profile is inserted into a supporting structure and secured in captive fashion by pins.
An escalator step of the generic type is known from DE 196 51 585 A1. A plastic edge strip is extruded over the side edges and the front edge of the step body. The step body has a flange region which can be introduced into an injection mould and have plastic injected over it. The injection mould is made up of a mould element, a mating mould element and of the flange region of the step body. Three mould elements thus have to be assembled with sufficient sealing force for the plastic injection moulding.
It is an object of the invention to provide a step for escalators which has the lowest possible overall weight and can be produced in a straightforward production process without any additional assembly outlay.
The foregoing object is achieved by providing a step for escalators comprising a tread and an arcuate skirt adjoining the tread, the tread and the skirt have reinforcing ribs and/or reinforcing spars arranged on an inner surface in order to reinforce the step, and a connecting structure is provided for connecting the step to a drive arrangement between a front edge region of the tread, as seen in the direction of escalator travel, and a remote edge region of the skirt. The step may be produced from a light-metal casting, and preferably the outer surfaces of the tread and of the skirt are formed from plastic by injection moulding.
It is advantageous for the step, as far as possible, not to be affected by dirt and to be capable of being cleaned as easily as possible. This is achieved in that grooves and ridges running in the longitudinal direction of the escalator are formed on the outer surface of the tread, and in that further grooves and ridges are formed on the outer surface of the skirt, the ridges having a plastic coating which covers the surfaces on all sides.
It is further advantageous for the step to have the lowest possible overall weight. This is achieved in that grooves and ridges running in the longitudinal direction of the escalator are formed on the outer surface of the tread, and in that further grooves and ridges are formed on the outer surface of the skirt, the ridges being formed entirely from plastic by injection moulding. The plastic material for the coating may be selected such that the outer surface, which is subjected to the highest level of wear, can easily be cleaned or can even be rendered dirt-repellent. The plastic material can be dyed in different colours during formulation or provided with colour subsequently.
It is also advantageous that the step can be produced in a straightforward process. This is achieved in that formed in the casting between the outer surfaces and the inner surfaces of the tread and of the skirt are through-passages, which have the plastic injected through them from the outer surface to the inner surface during injection moulding. The step, which is produced, in a first process stage, as an aluminium casting by diecasting, is accommodated entirely in an injection mould in the following process stage and has the plastic material injected over the entire surface area at least of the outer surfaces.
It is further advantageous for the plastic coating of the step to be connected to the aluminium casting in as durable a manner as possible and with the best adhesion possible. This is achieved in that in the region of the through-passages, on the inner surface, anchorage means are moulded in one piece with the plastic coating on the outer surface.